Here's the breakdown:
* If you're simply changing brake pads: You likely *won't* need to depress the pistons. Modern brake calipers usually have pistons that automatically retract as the pads wear down. If they don't move enough, you may only need to use a C-clamp carefully (see below). Forcing the pistons in without understanding how your caliper works risks damage.
* If you ARE replacing brake pads and the pistons won't retract enough: You'll need a specialized tool. Avoid using screwdrivers or other makeshift tools which could damage the piston seals.
* C-clamp method (use with caution): Place a piece of wood or thick metal between the caliper piston and the C-clamp jaws to distribute pressure evenly. Slowly and carefully compress the pistons. Watch out for brake fluid spraying! Have a rag handy and consider using a plastic bag to cover the piston to contain any spilled fluid. You'll need to turn the piston(s) as you compress to allow even retraction.
* Caliper piston compression tool: Auto parts stores sell specific tools designed for this job. These tools distribute pressure evenly and prevent damage. They are highly recommended.
* If you're working on something else entirely and need to compress the pistons: Again, using the appropriate tool is key to avoid damage.
Crucial Considerations:
* Brake Fluid: As you compress the pistons, brake fluid will be displaced. Make sure the brake fluid reservoir is checked and topped off *before* you start. Overfilling can damage the system.
* Safety: Always work on a level surface with the parking brake engaged. Never work under a vehicle without proper jack stands.
* Consult a Repair Manual: A repair manual specific to your 2006 Pontiac G6 will provide detailed instructions and diagrams for your specific model. This is highly recommended before attempting any brake work.
In short: Unless you are *absolutely sure* you need to depress the rear caliper pistons (and understand *why*), don't attempt it. If you're just changing brake pads, start by trying to install the new pads without forcing anything. If the pads won't fit, carefully use a C-clamp or, preferably, a dedicated caliper compression tool. If you're unsure, consult a qualified mechanic. Brake systems are complex and safety-critical. Improper work can have serious consequences.
